Facebook Invite All Subrange

Adds a "Toggle subrange" friends button to facebook groups, events, and pages invite boxes, which lets you select subranges of your friends in one click.
Why?
There are reasons to believe that facebook is blocking mass invites to more that 4000 friends or so. With this extension you can invite friends in groups of thousands in such a manner to send invites with delays. When you send invites to first thousand you make a pause. After a few minutes or the whole day send to the next thousand. Just remember where you stopped :)
Usage:
- first input box is starting position
- second input box is count
- click "toggle subrange" to toggle selection!
eg.
1, 1000 - select 1000 friends staring with first
1000, 500 - select 500 friends staring with 1000th
(based on Facebook Invite All)